Resin-shaped articles are produced for various applications such as electric or electronic parts, auto parts and building materials.
In these resin-shaped articles, at least one kind of resin and at least one kind of additive are applied for obtaining of required performance depending on an object.
For example, in electric or electronic parts such as transistors and IC, plastic sealing using a epoxy resin composition is adopted mainly.
Plastic sealing with the epoxy resin composition is excellent in mass productivity and products can be obtained cheaply.
However, in plastic sealing, stress relaxation after the sealing happens as a big problem because coefficient of linear expansion of a resin is higher than the one of a semiconductor element.
In addition, epoxy resins are much applied to insulating layers of laminated sheets for electric insulation or printed wiring boards.
In recent years, printed wiring board-mounting technologies have been improved and using-conditions of printed wiring boards have been changed.
So, demand for getting reduction in elastic modulus is high.
In each of Japanese Patent Laid-Open No. 2000-7,890 and Japanese Patent Laid-Open No. 2004-315,572, there is proposed a method to blend a graft polymer obtained with graft polymerization of a monomer mixture onto a rubber particle as a method to get reduction in elastic modulus of an epoxy resin-shaped article.
In Japanese Patent Laid-Open No. Hei 5-65,391, there is proposed a method to blend a graft polymer obtained with graft polymerization of a monomer mixture containing a cross-linkable monomer onto a rubber particle as a method to improve storage stability of an epoxy resin composition.